Posted
by
kdawson
on Monday November 22, 2010 @09:31AM
from the whole-lotta-shakin dept.

swellconvivialguy writes "Next year marks the bicentennial of the 1811-12 New Madrid earthquakes, with earthquake drills and disaster tourism events planned across the Midwest, including the Great Central US ShakeOut. But despite the fact that Earthquake Hazard Maps equate the New Madrid seismic zone with California, geologist Seth Stein says new science (especially GPS data) tells us that the hazard has been significantly overestimated, and that we should not spend billions on earthquake preparations in the Midwest."

When we look at faults around the world, we see them storing up that energy. So when we first put markers in the ground and measured the position of the Midwestern fault lines we were surprised that we didn’t see any motion at New Madrid. We concluded that there’s no sign that a big earthquake is on the way.

I'm not a geologist so I'm very confused, if something is 'storing up energy' how does moving around equate to that? I mean, if the moving of the ground in violent ways is the releasing of that 'stored energy' then how is small movements indications that it's storing up energy? I would assume that the worse earthquake areas are those when there's a lot of movement going on deep underground but nothing on the surface releasing that energy until a very devastating movement.

So from the Wikipedia article:

The lack of apparent land movement along the New Madrid fault system has long puzzled scientists. In 2009 two studies based on eight years of GPS measurements indicated that the faults were moving at no more than 0.2 millimetres (0.0079 in) a year. This contrasts to the rate of slippage on the San Andreas Fault which averages up to 37 millimetres (1.5 in) a year across California.

Can somebody who knows a lot about this stuff explain to me why we are so sure that a lack of movement in GPS measurements indicate no potential earthquake? My intuition would guess that no movement is not a good indicator either way unless we've figured out how to drive GPS receivers down into the faults themselves and retrieve that information. I think they're just ground stations [nasa.gov] that are taking these GPS measurements, right?

What about the northern earthquakes [slashdot.org]? Do GPS stations up there report tiny movements in the crusts leading up to those earthquakes? I'm just curious if it's possible that you're dealing with different kinds of faults when comparing the San Andreas fault line versus the Ramapo fault line versus the New Madrid fault line.

What we’re learning is that faults switch on and off. They will be active for a thousand years or so, and then inactive for several thousand years. And then other faults may become active. From a scientific standpoint, that’s the really exciting thing we’ve learned from New Madrid. It has been the key to the door that opened up a whole new understanding about how faults inside continents work.

This sounds, at best, questionable or highly fitted to very recent events that we've had the privilege to watch. It's difficult to look over long swaths of time historically when our precision instruments for measuring are a very recent thing compared to the age of the crust. I'm not arguing for the spending of billions in the mid-west but I'm not sold on a single expert's opinion, is this consensus in the geological community?

if something is 'storing up energy' how does moving around equate to that? I mean, if the moving of the ground in violent ways is the releasing of that 'stored energy' then how is small movements indications that it's storing up energy?

I am not a geologist either, but if I hold one end of a rubber band still and move the other in one direction, it stores up energy. Releasing the rubber band releases that stored energy by moving in the other direction in a violent (and possibly painful) way.

In my mind I'd see it more like trying to remove a pressed wheel bearing. For example I have an OTC Hub Tamer Elite that has a C shaped part you put between the knuckle and the hub/rotor assembly, and then a J shaped piece that goes off of the C and ends up on the other side of the knuckle aligned with the hole in the wheel bearing. You put a long high strength bolt down the middle of the wheel bearing and into a disc, and then put a nut on. You hold the nut, and use an impact to drive the bolt. The bolt ca

To further that analogy, when you put one end of the rubber band around the end of your finger, say, and pull it back with the other hand, the end around your finger will start to roll up closer to the end of your finger as you pull harder and harder until it finally snaps off the end of your finger. The small movements geologists look for as a warning of impending earthquakes are similar to the rubber band rolling up your finger as more and more energy is stored in the rubber band. Just because the end of

I'd think of it like a boiler. When it's not under a lot of pressure there is no movement, but when the pressure gets higher it begins to shake, and when it's about to blow it shakes more violently. Similar to volcanoes I suppose. IANAG

When we look at faults around the world, we see them storing up that energy. So when we first put markers in the ground and measured the position of the Midwestern fault lines we were surprised that we didn’t see any motion at New Madrid. We concluded that there’s no sign that a big earthquake is on the way.

I'm not a geologist so I'm very confused, if something is 'storing up energy' how does moving around equate to that? I mean, if the moving of the ground in violent ways is the releasing of that 'stored energy' then how is small movements indications that it's storing up energy? I would assume that the worse earthquake areas are those when there's a lot of movement going on deep underground but nothing on the surface releasing that energy until a very devastating movement.

the difference between and earthquake, and not is how QUICKLY the energy is released.

think of it this way.. take X amount of energy and bend a piece of wood over 100 years. take that same amount of energy and apply it in 10 seconds. Over a hundred years, you'll end up with a bent piece of wood.. in 10 seconds, you get a snapped piece of wood. tectonic movement is slow bending, earthquakes are the snap. you don't notice a shift of an inch over 20 years, but in an earthquake, it's shifting FEET in SECONDS.. s

As to movement, I think they generally take points away from the fault, say 50 or 100 miles on each side and look at the relative movement of each. This does not mean that each side of the fault line has moved relative to one another, it's more like bending a plastic ruler, it has some give in it, but move too much and it'll snap. So the amount of relative movement of each side can give you an idea how much energy is stored and therefore how big the earthquake is going to be. As it's not like roads on the f

The scientific and engineering consensus is that there is an earthquake hazard in the central US. New Madrid had three massive events at around ~M8.0 200 years ago, a dozens of M6.0 events, and there is paleontological evidence showing that these earthquakes have occurred every few hundred years dating back quite some time. The USGS gives the New Madrid seismic zone a 25-40% chance to have a M6.0 or larger earthquake in the next 50 years. I might note that seismic waves in this area travel significantly farther due to the older, less smashed-up ground underneath this region of the country. Additionally, the New Madrid seismic zone is filled with up to 1km of thick sediment. How, exactly, seismic waves propagate through thick sediment is still undergoing much study, but we do know that they focus earthquake energy, and studies in Taipei have shown that sharp velocity gradients in the sediment can double the peak ground acceleration of an earthquake at the surface.

Seth Stein and a few others in the GPS area look at surface measurements as the only sign for strain to build up causing an earthquake. This works with very pretty models of earthquakes, like near San Andreas and Eric Calais' famous "Haiti prediction" (he looked at the strain rates, calculated how much strain had built up since the last earthquake, and stated that if an earthquake were to happen soon, it'd be ~M6.8 or so), but it breaks down significantly for inter-continental seismic zones. The New Madrid seismic zone is one of those zones, and it is poorly understood. However, it doesn't take brain-busting thinking to entertain the idea that strain rate at the surface doesn't mean that nothing is happening at the subsurface, and, in fact, the New Madrid seismic zone has very frequent small magnitude earthquakes every day.

The scientific consensus is that the New Madrid seismic zone presents a serious seismic hazard based on tons of historical evidence and current seismological research. Seth Stein is the devil's advocate to that view and frequently and very public tells the world that there will never, ever be another big earthquake in New Madrid, ever. He is in the minority.

I might note that seismic hazard assessment for Wenchuan, China, was rated very highly in the 1950s due to historic evidence of horrible earthquakes in that area. Since the 1950s, the Chinese seismic hazard map has been revised several times and, due to very very slow strain rates measured by GPS, Wenchuan's risk of a catastrophic earthquake was downgraded to basically negligible. In 2008, however, we all saw that massive M7.9 that struck and killed so many people in this area where strain rates were "too small for a large earthquake."

I also might note that physicists at USGS have used the very same data that Seth Stein collected and used, and when they subtracted out the average movement of the North American continent, they found strain rates in the central US that were very high, more than enough to create a catastrophic earthquake. There is more than one way to interpret Stein's data.

I'm not much interested in geology, but I'm very interested in paleontology and you can't do much paleo without reading a lot of geological papers. I was not terribly pleased with the article which seemed kind of hazily optimistic to me. Even more so after checking recorded quakes and finding eight in California in the last century strong enough to do a major damage and in most cases result in fatalities. Using the article's own numbers (ten times as likely in Cali

It seems like geologist are not the right people to define spending based upon sound risk assessment principles. Based upon how likely the even is to occur (in this case it certainly will occur how often is the only question), the impact upon human life and infrastructure of the event occurring (very severe), all versus the cost of taking precautions to mitigate the losses suffered (far less than the expected losses if no precautions are taken).

Was going to give eldavojohn a tl;dr flame because he sounded a bit like one of those bad slashdot commenters dissing scientists' real work in favor of intuition, but I recognize his nick and that's not his style. On rereading, Eldavojohn prolly is asking like he did because he's curious and the issues seem counterintuitive, not because he thought he was being insightful (stupid mod system needs a '+1 good question')

Earthquakes and plate tectonics don't map ideally to simple, intuitive physics. Then again

I'm not a geologist so I'm very confused, if something is 'storing up energy' how does moving around equate to that? I mean, if the moving of the ground in violent ways is the releasing of that 'stored energy' then how is small movements indications that it's storing up energy? I would assume that the worse earthquake areas are those when there's a lot of movement going on deep underground but nothing on the surface releasing that energy until a very devastating movement.

Full disclosure: I am a geologist, but I don't study intra-plate earthquakes and I'm not familiar with Stein's work. You're correct that the faults themselves are locked, so there's no relative motion immediately to either side of the fault. But the strain accumulation is caused by the relative motions of much larger crustal blocks, and this movement can be seen using GPS. Saying "the faults are moving @ x mm/yr" is incorrect short-hand for saying "the relative motion of the crust on either side of the faul

Just wait until California gets a divorce. It's the geologic celebrity moment we've all been waiting for. It'll probably keep the engagement ring too... I mean since she's wracked up so much debt and all...

My mind always reads that as "I anal", or in "I'm anal", Which makes sense if you're a lawyer meaning anal in the psychological sense, but it has certain sexual overtones as well that I don't want to think about on a website mostly populated by men.

Now you've invented an acronym for saying you're not a seismologist, IANAS, and my brain processes it as "I anus" or "I'm an anus."

Never mind why you have low self esteem: basically I just want to read about earthquakes and legal issues without thinking about so much goddamn anal and anuses.

I think the problem here is yours rather than his. I sometimes find the IANAL acronym amusing, but I don't think I noticed immediately the word ANAL in it, and even after I did I just found it amusing.

There was a year or two in my life where I had some serious OCD going on, apparently aggravated as a side effect of coming off of anti-depressants (though once I read about OCD I could see I've had it all my life, it does explain a lot of stuff I have thought/done), and it made many things disturbing, but you

Money would be better spent making a few places secure for winter time emergencies. Unlike California, if we're without power or housing, we die.

If you look at the map [wikimedia.org], you'll see that the New Madrid fault line is mostly in Missouri and will affect several states further south. It won't even touch Minnesota. Serious earthquakes are pretty rare, even historically [umn.edu] in Minnesota.

I don't know what the winters are like in Missouri and I don't know if many people die from them down there. The threats from poor driving on the road are probably their biggest problems and I don't know if any amount of money will fix that sort of behavior. I grew up n

I don't know if it would hit quite the population that the San Andreas could but you're talking about a potential large area without utilities, increased lawlessness and a logistical nightmare for support/rescue.

Don't forget this large area feeds an even larger area. Earthquake hits in December, probably best case scenario. Earthquake hits in April, no planting, sourcing food next winter will be rough but we have time to make plants and import. Earthquake hits in, say, August, big trouble in just a couple months.

I'm failing to see how an earthquake would destroy the crops in the midwest. Sure, there could be damage some farmers like having equipment destroyed and going bankrupt, but your scenario implies outright destruction of a fair portion of the midwest farms. (The US does have exports, Food being a big one.)

The only possibility I can think of that's even remotely like that is wholesale destruction of grain elevators.

Scale : One tipped over combine harvester is no big deal for the village's single tow truck and the villages single mechanic, and the regional tractor distributor probably has "a" spare part in stock. And his neighbor is probably friendly and OK. On the other hand, when ALL the harvesters / tractors in one area tip over or are crushed by collapsed barns etc, then we all have a bi

The 1812 New Madrid quake caused part of the Mississippi to flow backwards for a time to fill Reelfoot lake. Between that and any collapsed bridges, I wouldn't be so sure the river would be navigable immediately.

I think the biggest problem would be a quake that took out a number of Mississippi or Missouri River bridges. Other than that even earthquake prone California and Japan have had few earthquake related agricultural problems.

Winters are cold and snowy. Not so much in southern Missouri, but it still freezes.

When tornados hit Springfield, IL and took out power to half the city, in March when it was still winter (an ice storm came a week later), there was no increased lawlwssness. No looting at all, no increased violence. People were too busy rebuilding.

I agree. Point is that it would be better in a low risk area to invest in disaster preparation to keep people alive and communications open than to over-develop and waste dollars to update the infrastructure.

Indeed; one week in March 2006 we had wind, rain, nice weather, freezing weather, hail, sleet, snow , ice storms, and two tornados -- all in the same week. It was fortunate that the electrical infrastructure was rebuilt in a week, because the day after the last building got powere back, it froze again and we had another ice storm.

Ice storms take out power lines, but tornados take out everything -- poles, transformers, the works.

This is part of a vast, left-wing conspiracy to rid the nation of the so called "fly over" country and its citizens, thereby keeping the current "leadership" in place. Since they won't be prepared, the ensuing earthquake will render "Middle America" unlivable and force those from the middle of the US to the coastal areas and force them into Welfare.

The New Madrid fault is totally different from the faults in California. The earth in and around the New Madrid fault lines are covered with millions of years of river silt, clay, and other soft strata. It is several miles underground making observation of its activity difficult at best. The most observable activity is the sand boils. They usually indicate pressure pushing up to the surface. The faults in California are within harder, drier strata, making them much easier to see, even with the naked eye. The plates which make up the faults in CA also move with greater frequency causing the strata around them to be splintered with spiderweb cracking, making them easier to move when pressure builds up. The New Madrid fault doesn't move much because it is not along a significant induction/subduction area between plates like those in CA (though the plates on the coast are not actually diving under one another but rather rubbing against each other). This is why the last major quake at New Madrid was so large. There's very little movement to reduce the strain.

Yes.
It's surprising that he seems to gloss over this fact (and the physical evidence of many earlier major earthquakes in the area.) I assume the article does not present his argument well.
As a geology grad and Illinoian who has experienced tremors in southern Illinois first hand, I will not be one to dismiss the dangers of the New Madrid fault anytime soon. Just two years ago I had pots in my kitchen cabinets rattle from a tremor in the area, and I live 350 miles away, near Chicago. I think his view (as

Interestingly enough, the article focuses on downplaying the danger of New Madrid, but it also glazes over the comment Dr. Steins made about observing GPS data that would indicate pressure building up near Oregon/Washington/Utah. Though I'm sure his work has scientific value, the article that this slashdot story is derived from has none given how quickly they are to dismiss the midwest and northwest fault information and activity. It tells me that they were more interested in controversy than scientific kno

That comment from the geologist looks like the perfect way to summon the Murphy undergod. May be it wouldnt was to happen anything bad before, but now the resulting megaquake will even trigger the Yellowstone supervolcano.

The theory of plate tectonics easily explains the earthquakes at the boundaries of tectonic plates due to the differential grinding motions of these plates.
New Madrid is one of the 10%-15% of earthquakes that does not happen a current plate boundary, so its cause is less clear.
There are motions of sub-blocks inside a plate. But these are typically an order of magnitude less that at established plate boundaries.
So it may take millennia to build the same kinds of strains (20+ feet) it only takes centuries in a place like California.
Geophysicists are divided by the amount of strain at New Madrid. Dr. Stein's group only sees a small amount in GPS data. Others see a lot more.
The data has noise. Its quality depends on the experimental setup. The more stations you record, the more complexity you see.

The US government and university scientists are spending a lot of money and effort to understand the New Madrid area.
It more a lack of understanding of intra-plate earthquakes than the amount of money spent.
In this era of "no risk is too small" political correctness (e.g. TSA) perhaps no government authority is willing to demote
The New Madrid risk as Dr. Stein claims.

Some sections of the Mississippi River appeared to run backward for a short time. Sand blows were common throughout the area, and can still be seen from the air in cultivated fields. The shockwaves propagated efficiently through midwestern bedrock. Residents as far away as Pittsburgh and Norfolk were awakened by intense shaking. Church bells were reported to ring as far as Boston, Massachusetts and York, Ontario (now Toronto), and sidewalks were reported to have been cracked and broken in Washington, D.C."

Because I know/. has significant international readership, I'd like to point out that we don't say "New Meh-DRID", like the city in Spain; but "New MAH-drid" (rhymes with "Eldred").

Also, I live in St. Louis and was 9 years old when Irving Browning predicted, to the day, when the fault go off [semo.edu]. In the paranoia, some students practiced earthquake safety (crouching under your desk).

Mountain Grove Missouri closed their entire school system that day. I distinctly remember having a new NES game and being particularly annoyed that I was explicitly told not to stay inside at any point of the day for more than a few minutes.

The government will decide to do earthquake (building damage) mitigation only when they figure out a way to funnel the money to a small group of select contractors who have spent a lot of money getting them elected. So when Haliburton decides it has milked the Middle-East situation for all it can get and decides Mid-West earthquake mitigation is its next profit center, then we will see more mitigation than there is any need for. Suddenly the media will be up in arms about the pending disaster to the Mid-Wes

It strikes me as one hell of a coincidence that this article comes up shortly after Nebraska experienced a 3.3 magnitude earthquake last week (11/18/10). More information can be found here [noaa.gov]. The cows were producing curdled milk for days...

We had a 4.3 here in central Oklahoma back on 10/13, and it was noticeable only as a peculiar heavy vibration. One jokester was sending around a photo of "earthquake damage". It was a back yard table and chairs set with one of the plastic chairs knocked over.

That depends on what type of material the surrounding area is made of. in the softer soils of the midwest, a small quake can still lead to some liquification of the soil and seemingly magnify the intensity of the quake.